Control device for mining equipment

ABSTRACT

The invention relates to a device which can be used in the remote control technique in mining and in particular hydraulic mining and serving for the conversion of a hydraulic pressure into a pneumatic analog pressure signal. The device has a diaphragm which is subjected on one side to hydraulic pressure and on its other side to constant pneumatic pressure. The diaphragm is arranged in a pressure chamber which has an output for the analog signal and a connection for the constant supply of pneumatic line pressure. An axially adjustable tube has an end facing the diaphragm and provides an annular slot with the diaphragm. The tube has bore open to the outside. A plurality of spring washers resist diaphragm deflection in a unique manner.

United States Patent CONTROL DEVICE FOR MINING EQUKPMIENT 5 Claims, 1 Drawing Fig.

US. Cl 73/406 Int. Cl G01l7/08 Field of Search 73/406,

408, 388 EN, 388 R [56] References Cited UNITED STATES PATENTS 3,277,721 lO/l966 Bader 73/408 Primary Examiner-Donald O. Woodiel Attorney-Malcolm W. Fraser ABSTRACT: The invention relates to a device which can be used in the remote control technique in mining and in particular hydraulic mining and serving for the conversion of a hydraulic pressure into a pneumatic analog pressure signal. The device has a diaphragm which is subjected on one side to hydraulic pressure and on its other side to constant pneumatic pressure. The diaphragm is arranged in a pressure chamber which has an output for the analog signal and a connection for the constant supply of pneumatic line pressure. An axially adjustable tube has an end facing the diaphragm and provides an annular slot with the diaphragm. The tube has bore open to the outside. A plurality of spring washers resist diaphragm deflection in a unique manner.

CONTROL DEVICE FOR MINING EQUIPMENT SUMMARY OF THE INVENTION Formation of the analog signal occurs in this device by variation of the annular slot on account of the varying fluid pressure and thereby caused varying throttling of the outlet opening. Such a device can be miniaturized, and is therefore well suited, for instance, for indication with the aid of a pneumatic signal of the high hydraulic pressure in the cylinder of a hydraulic mining ram.

In my copending application, Ser. No. 716,593, the deflection of the diaphragm is used exclusively for varying the annu lar slot. The slot width and, thus, the magnitude of the analog signal is in that case not linearly dependent on the fluid pressure. This is troublesome in some cases of technical application.

In accordance with the invention, a supporting spring is provided with progressive characteristic curve and is arranged below the diaphragm within the pressure chamber. The diaphragm is deflected to a relatively large amount in the range of low fluid pressures, but that at increasing pressures the deflection of the diaphragm becomes less, that is, that the increase of hydraulic pressure by one unit of pressure will correspond to a smaller deflection of the diaphragm.

The spring under the diaphragm consists conveniently of a plurality of spring washers spaced from each other and clamped axially with relation to the annular slot. It is ad vantageous if the spring washers are of annular shape and the ring diameters increase in the direction of the spring action.

BRIEF DESCRIPTION OF THE DRAWING The figure is a longitudinally sectional view of a remote control device embodying the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The device has a device body 1, which consists of parts 2 and 3. The upper part 3 of the drawing is screwed into the part 2. Part 2 has an annular flat supporting surface 4 for supporting a diaphragm 5, which, in this instance, is of circular shape. The screwed-in part 3 has a flat annular surface 6 opposite to the surface 4, and an annular seal 7, in order that the diaphragm is pressed liquidtight onto the supporting surface 4 when the parts are screwed together.

The screwed-in part 3 has a central hole 8, which is provided with internal threads 9. The hole 8 serves to receive a connection, such as a tube or hose, which serves for admission ofa pressure fluid. The liquid under pressure acts upon the exposed surface Sa of the diaphragm 5, and can originate from the pressure cylinder of a hydraulic mining ram (not shown).

The larger body 2 of the device is provided with a circular chamber 12, which forms a pressure space, one side 50 of which is closed off by the diaphragm 5. The side b of the diaphragm which lies opposite to the side 5a, is exposed to compressed air which is fed into the space 12 at constant pressure by way of an annular channel 16 through an internally threaded hole 15. The hole or fitting thus forms a connection for admission of compressed air into the device.

Opposite to the connection formed by hole 15 is an outlet hole 19, provided with internal threads 18, at which the analog signal is generated in a manner to be described.

The end of a tube 20 which faces the diaphragm 5 and is screwed into a corresponding hole at 21 and is sealed at 22 with a ring seal, protrudes centrally into the circular chamber 12. A nut 23 serves for the axial adjustment of the tube in the hole, and thus for the adjustment of the size of an annular slot 24 which is formed between the tapered nose constituting the free end of tube 20 and the side 5b of diaphragm 5. The clear bore 25 of tube 20 leads from chamber 12, to the outside. Compressed air from the fitting 15 flows into chamber i2 from which it can pass through the hollow base 25 of the tube 20 and thence to the outside.

Located below the diaphragm 5 in the pressure chamber 12 is a support spring with progressive yielding characteristic, the spring consisting of annular spring washers 40 and 41 clamped at a distance from each other axially with relation to the annular slot. The spring washer 40 has an annular opening 43, and the spring washer 41 has an annular opening 42. The openings 42 and 43 are of different diameters. In direction of the spring movement these diameters increase, so that diameter of the opening 43 is smaller than that of the opening 42.

Fluctuations of the fluid pressure on side 5a of diaphragm 5 lead initially to a deflection of the diaphragm and a diminution of the annular slot 24 so that the discharge of compressed air from the chamber I2 will be more or less restricted. In consequence an air pressure is generated in chamber 12 which can be sensed at 19.

On increasing fluid pressure and increasing spring travel of the diaphragm 5, the diaphragm will rest finally on the inner edge of the first spring washer 40 when viewed in an axial direction, and will deflect this spring washer. After the spring washer 40, the spring 41 starts acting on a further pressure rise. By a corresponding number of spring washers it is possible to attain a progressive spring travel and thus a far reaching linearity of the relation between fluid pressure and pressure analog signal.

From the above, it will be understood that the analog air pressure introduced through the duct or hole 15 passes through the annular passage 16 to the pressure chamber 12, and thence to the outlet duct or hole 19. The hole or duct 19 may be suitably connected to a pressure gauge (not shown) which by suitable calibrations of the scale thereof, the scale can be made to read directly in tons or other units of weight acting on the hydraulic ram of the pit prop. Since the hydraulic pressure is introduced through the duct 8 and applied to the top face 5a of the diaphragm 5, any variation or alteration in such pressure causes a deflection of the diaphragm, thereby to vary the width of the gap between the tube 20 and the lower face 5b of the diaphragm. As a result, a greater or lesser pressure gradient across the gap is created in the air pressure produced in the chamber 12. The spring washer arrangement, involving the spring washers 40 and 41, enables such movement of the diaphragm that the diaphragm is deflected a large amount in the range of low hydraulic pressures, but the deflection is less at increasing pressures.

What I claim is:

I. A device for indicating by pneumatic signal the hydraulic pressure of a mining ram comprising a body provided with a pressure chamber, a diaphragm spanning said chamber and dividing it into separate sections, duct means for conveying hydraulic pressure fluid to one chamber section to impinge against one side of said diaphragm, an open-ended tube extending into the other chamber section and terminating adjacent the other side of said diaphragm, the other end of said tube being open to the outside, means to conduct a stream of air under constant pressure through said other chamber secion to pass to the inside of the tube and thence to the outside, whereby any variation in hydraulic pressure causing flexing of said diaphragm so as to vary the gap between the end of said tube and said diaphragm creates a varying pressure gradient across said gap, and a supporting spring device having a progressive yielding characteristic disposed adjacent said diaphragm in said chamber section to support the diaphragm upon the deflection thereof with increasing hydraulic pressure.

2. An indicating device as claimed in claim 1, in which said spring comprises a plurality of members clamped in place and spaced axially from each other and disposed in the region of said gap.

3. An indicating device as claimed in claim 2, in which said spring members comprise spring washers of annular shape, the diameters of the hc.cs in said washers increasing in the direction of spring travel.

4. An indicating device as claimed in claim 2, in which said spring members comprise annular spring washers, the diameter of the holes thereof being different and the washers closer body consists of two parts secured together, and said spring to said diaphragm having the smaller holes. comprises washer annuli the edge portions of which are 5. An indicating device as claimed in claim 1, in which said i clamped in placelay said body parts. 

1. A device for indicating by pneumatic signal the hydraulic pressure of a mining ram comprising a body provided with a pressure chamber, a diaphragm spanning said chamber and dividing it into separate sections, duct means for conveying hydraulic pressure fluid to one chamber section to impinge against one side of said diaphragm, an open-ended tube extending into the other chamber section and terminating adjacent the other sidE of said diaphragm, the other end of said tube being open to the outside, means to conduct a stream of air under constant pressure through said other chamber section to pass to the inside of the tube and thence to the outside, whereby any variation in hydraulic pressure causing flexing of said diaphragm so as to vary the gap between the end of said tube and said diaphragm creates a varying pressure gradient across said gap, and a supporting spring device having a progressive yielding characteristic disposed adjacent said diaphragm in said chamber section to support the diaphragm upon the deflection thereof with increasing hydraulic pressure.
 2. An indicating device as claimed in claim 1, in which said spring comprises a plurality of members clamped in place and spaced axially from each other and disposed in the region of said gap.
 3. An indicating device as claimed in claim 2, in which said spring members comprise spring washers of annular shape, the diameters of the holes in said washers increasing in the direction of spring travel.
 4. An indicating device as claimed in claim 2, in which said spring members comprise annular spring washers, the diameter of the holes thereof being different and the washers closer to said diaphragm having the smaller holes.
 5. An indicating device as claimed in claim 1, in which said body consists of two parts secured together, and said spring comprises washer annuli the edge portions of which are clamped in place by said body parts. 